The present invention relates to the field of pest management, pesticides, and general pest control strategies.
Insect pests cause substantial damage to stored food products throughout the world and thus are considered major pests worldwide. Stored grain insect infestations rarely begin in the field and instead tend to develop from small numbers of pests already present in or around farm storage bins. Insects in stored grain affect grain quality; and therefore insects. Direct-feeding damage by insects reduces grain weight, nutritional value, and germination of stored grain. Insect pests also cause damage in humans and animals by their presence, either alive or dead, in grain that is to be processed for food. Investigations also cause contamination, odor, mold, and heat-damage problems that reduce the quality of the grain and may make it unfit for processing into food for humans or animals. For these and other reasons, the presence of pests above some de minimis amount is generally considered unacceptable in domestic grain supplies.
Small grains, including wheat, are harvested in spring and stored through the hottest and most humid months of the year. These conditions make it extremely difficult to prevent damage. Commercial grain buyers may refuse to accept delivery of insect contaminated grain, or may pay a reduced price. In the United States alone, the yearly post-harvest losses due to insects in corn and wheat are estimated at about $1.25 billion to $2.5 billion, accounting for 5-10% of the total value of corn and wheat produced (USDA, 2005).
The principal pests that cause damage are the adult and larval stages of beetles, and the larval stage of moths. Tenebrionidae (“darkling beetle”) is a family of beetles that known to be one of the major pests in agricultural systems and products. The insects feed on durable stored products that humans use and consume such as cereals, cocoa beans and dried fruit. The presence of Tenebrionidae decreases the quality and quantity of such commercial food products, and in some cases they have depleted post-harvest food such as corn in developing countries by up to 10%. This is especially detrimental where food is scarce.
The darkling beetle is also a common problem in poultry facilities because the beetles tend to both consume the poultry feed and carry and transmit diseases to the poultry itself. Poultry is a leading agricultural industry in many states. For example, poultry is the number one agribusiness in North Carolina accounting for 110,000 jobs and generating an annual economic impact for North Carolina of $12.8 billion (NC Poultry Federation). Upon the infestation of a poultry house by relatively few of these insects, their numbers can extend into the millions within a few weeks. For example, a poultry house with 20,000 broiler chickens may be moderately infested by about 4 million beetles. During a typical 50 day grow-out period (i.e., the growth cycle for the fowl) these beetles can consume 400 pounds of poultry feed. Even more importantly, beetles may be carriers of pathogenic organisms, such as E. coli, salmonella, tapeworms, and cecal worms. According to the FDA, three common pathogens (Salmonella, Listeria, and Toxoplasma), are responsible for hundreds of human deaths and tens of thousands of hospitalizations every year.
One of the most common insecticides used to try to control insects in stored grain and other applications are in a class known as organophosphates. Although many organophosphates are important biochemicals, others are toxic to insects and animals, and some are the basis for nerve agents that can detrimentally affect humans. For this reason, organophosphates have been banned for use in home insecticide products in the US. Organophosphates are thought to degrade after application and thus widely used in agriculture, but health risks remain high for farmers, food-workers, and other non-target insects and animals that come in contact with the chemical in the environment.
Pyrethrum-based insecticides are the primary alternative to organophosphate insecticides. Pyrethrum has the advantages of it natural source and its low toxicity to humans (although larger amounts can affect the nervous system). As disadvantages, however, pyrethrum is a relatively high cost alternative, being imported primarily from East Africa and Australia; is a contact insecticide (i.e., requires direct contact with the pests); biodegrades in light; and is not persistent. Accordingly, many consumers are seeking safer, organic alternatives.
Accordingly a need exists for safer, more effective insecticides that target insect pests specifically without harming non-target animals and humans to continue to meet worldwide demands. Worldwide arable land per capita is declining, agricultural yield growth is slowing, and concerns about toxicity of many agricultural pesticides are increasing.